1. Field of the Invention
This invention relates in general to munitions and in particular to shaped charge follow-through devices.
2. Description of the Prior Art
The destruction of hard targets such as tanks long has been a major problem of explosive ordnance. Shaped charge technology has been developed to the point where the ability of a conical shaped charge to perforate a certain thickness of armor can be predicted with accuracy. It is known, however, that the perforation of protective armor may not be sufficient to comprise target defeat. For example, to defeat a tank or other armored vehicle sufficient damage must be inflicted to prevent successful vehicle operation and although prior art shaped charge technology may result in some damage resulting from fragmentation or spallation, sufficient personnel may survive to continue operation of the tank or other armored vehicle. The increased pressure within the target may cause damage to both personnel and material, and catastrophic kills can result if energy stored within the target such as fuel or ammunition is ignited.
Incendiary fragments have been mounted adjacent to the shaped charge liner wherein the incendiary fragments are attached to the surface of a liner and extend from the apex of the liner to the outer surface of the case such that incendiary fragments follow the jet and enter the target to provide the desired incendiary effect. Limited tests utilizing this technique show that only about 29 percent of the incendiary fragments penetrate the target and produce effective incendiary action. Such structure does not appear to be as efficient or effective as desired.
Another relatively simple approach of the prior art comprises incorporating incendiary material as a layer attached to the shaped charge liner so that it will be between the penetrating portion of the liner and the explosion. An incendiary used must be inert and one which is compatible with both the liner and the explosive. The incendiary must be machineable or easily worked in some manner to permit the fabrication of a precision liner that will not degrade shaped charge penetration. In practice it has been difficult to maintain tolerances of the primary liner and the incendiary liner for maximum effectiveness. A secondary problem exists where certain incendiary materials when fired into closed spaces which have insufficient oxygen are extinguished before being consumed. Oxygen depletion is an effective anti-personnel lethal mechanism but greater anti-material effectiveness can be obtained if the incendiary burns until consumed.
Yet another approach of the prior art is to provide an integral liner with a forward annular oxidizer wherein a forward annular compartment contains an oxidizer such as ammonium nitrate forward of the shaped charge liner to provide an oxygen atmosphere within the target. The annular chamber is dimensioned and positioned so that the oxidizer will be projected into the target by the aspiration effect of the jet while allowing unrestricted formation and travel of the jet. The use of a forward annular oxidizer with an integral liner with copper-aluminum and copper-magnesium and using ammonium nitrate as the forward annular oxidizer has successfully operated.
It has been known to replace the oxidizer of the forward annular oxidizer structure with a forward annular incendiary placed ahead of a simple liner. Tests utilizing this concept showed a 10 percent to 15 percent decrease in penetration.